Preparation of α-oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonic acid esters

ABSTRACT

A process for the preparation of an α-oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonic acid ester of the formula ##STR1## in which R is alkyl or a radical customary in the alcohol component of pyrethroids, and 
     R 1  is alkyl or phenyl, or the two radicals R 1  together are alkanediyl, 
     comprising reacting β,β-dimethyl-acrylic acid chloride of the formula ##STR2## with a phosphorous acid ester of the formula 
     
         R.sup.4 O--P(OR.sup.1).sub.2 
    
     in which 
     R 4  is alkyl, 
     at a temperature between about 0° and 100° C., to produce the novel compound 1-oxo-3-methyl-2-butene-phosphonic acid of the formula ##STR3## which is then reacted with a sulphuranylidene-acetic acid ester of the formula ##STR4## in which R 2  and R 3  each independently is alkyl or together are alkanediyl, 
     at a temperature between about 0° and 100° C.

This is continuation of application Ser. No. 288,444, filed July 30,1981, now abandoned, which is a division of application Ser. No.170,377, filed July 21, 1980, now U.S. Pat. No. 4,317,783.

The invention relates to an unobvious process for the preparation ofcertainα-oxo-α-(3-alkoxycarbonyl-2,2-dimethylcycloprop-1-yl)-methane-phosphonicacid esters (which can be used as intermediate products for thepreparation of pesticides) and to new intermediate products for thisprocess and to a process for their preparation.

α-Oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonicacid esters are the subject of German Patent Applications No. P 29 17260.3 [=No. Le A 19 632] and No. P 29 29 670.6 [=No. Le A 19 821].

The present invention now provides:

(1) a process for the preparation of anα-oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonicacid ester of the general formula ##STR5## in which R represents alkylor a radical customary in the alcohol component of pyrethroids and

R¹ represents alkyl or phenyl, or the two radicals R¹ together representstraight-chain or branched alkanediyl(alkylene),

characterized in that a 1-oxo-3-methyl-2-butene-phosphonic acid ester ofthe general formula ##STR6## in which R¹ has the meaning indicatedabove, is reacted with a sulphuranylidene-acetic acid ester of thegeneral formula ##STR7## in which R has the meaning indicated above and

R² and R³ individually represent alkyl or together representalkanediyl(alkylene),

if appropriate in the presence of a diluent, at a temperature betweenabout 0° and 100° C.;

(2), as new compounds, the 1-oxo-3-methyl-2-butene-phosphonic acidesters of the general formula ##STR8## in which R¹ represents alkyl orphenyl, or the two radicals R¹ together represent straight-chain orbranched alkanediyl (alkylene);

and (3) a process for the preparation of a1-oxo-3-methyl-2-butene-phosphonic acid ester of the formula (II) above,characterized in that β,β-dimethyl-acrylic acid chloride, of the formula##STR9## is reacted with a phosphorous acid ester of the general formula

    R.sup.4 O--P(OR.sup.1).sub.2                               (V),

in which

R¹ has the meaning indicated above and

R⁴ represents alkyl, preferably methyl or ethyl,

if appropriate in the presence of a diluent, at a temperature betweenabout 0° and 100° C.

It is surprising thatα-oxo-α-(3-alkoxy-carbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonicacid esters are obtained in very high yields by the process according tothe invention since, in reactions of β,β-dimethylacrylic acidderivatives with sulpuranylidene-acetic acid esters, the correspondingcyclopropane derivatives are in general formed only in low yields.

If, for example, 1-oxo-3-methyl-2-butene-phosphonic acid dimethyl esterand dimethylsulphuranylidene-acetic acid methyl ester are used asstarting materials, the reaction, according to the invention, of thesecompounds can be outlined by the following equation: ##STR10##

The process according to the invention described above under (1)("process (1)") is preferably carried out using a suitable solvent ordiluent. Possible solvents and diluents are virtually any of the inertorganic solvents. These include, as preferences, aliphatic and aromatic,optionally chlorinated hydrocarbons, for example pentane, hexane,heptane, cyclohexane, benzene, toluene, xylenes, methylene chloride,ethylene chloride, chloroform, carbon tetrachloride, chlorobenzene anddichlorobenzenes; ethers, for example diethyl ether, dibutyl ether,tetrahydrofuran and dioxane; and nitriles, for example acetonitrile andpropionitrile.

The reaction temperature in process (1) is in general kept between 0°and 100° C., preferably between about 20° and 80° C. The process is ingeneral carried out under normal pressure.

The starting compounds of the formulae (II) and (III) are usuallyemployed in approximately equimolar amounts for carrying out process(1), that is to say the molar ratio of the components is 1 to 1±0.1. Ina preferred embodiment of the process, the1-oxo-3-methyl-2-butene-phosphonic acid ester is initially introduced,if appropriate in one of the diluents indicated above, and thesulphuranylidene-acetic acid ester is added. The mixture of thecomponents is stirred at the temperature indicated above until thereaction has ended; the solvent is then carefully distilled off invacuo, whereupon the product of the formula (I) remains as an oilyresidue.

Formula (II) provides a definition of the new1-oxo-3-methyl-2-butene-phosphonic acid esters to be used as startingsubstances. Preferably, in this formula,

R¹ represents C₁ -C₄ -alkyl or phenyl, or

the two radicals R¹ together represent 2,2-dimethyl-propane-1,3-diyl.

Examples which may be mentioned are 1-oxo-3-methyl-2-butene-phosphonicacid dimethyl ester, diethyl ester and diphenyl ester and2-oxo-2-(1-oxo-3-methyl-2-buten-1-yl)-5,5-dimethyl-1,3,2-dioxaphosphorinane.

The new 1-oxo-3-methyl-2-butene-phosphonic acid esters of the formula(II) are obtained by the process described above under (3), by reactingβ,β-dimethylacrylic acid chloride of the formula (IV) above withphosphorous acid esters of the formula (V) above, for example withtrimethyl phosphite or triethyl phosphite or 2-methoxy- or2-ethoxy-5,5-dimethyl-1,3,2-dioxaphosphorinane, if appropriate in thepresence of a diluent, for example methylene chloride (or another of thesolvents indicated above for process (1)), at a temperature between 0°and 100° C., preferably between about 20° and 80° C., and if appropriatedistilling the crude product.

The phosphorous acid esters to be employed as starting materials areknown, as is β,β-dimethyl-acrylic acid chloride.

Formula (III) provides a definition of the sulphuranylidene-acetic acidesters to be used as further starting materials in process (1).

Preferably, in this formula,

R represents C₁ -C₄ -alkyl and

R² and R³ individually represent methyl or together representbutane-1,4-diyl (tetramethylene).

Examples of the starting materials of the formula (III) which may bementioned are: dimethylsulphuranylidene-acetic acid methyl ester, ethylester, n-propyl ester, iso-propyl ester, n-butyl ester, iso-butyl ester,sec.-butyl ester and tert.-butyl ester andtetramethylene-sulphuranylidene-acetic acid methyl ester, ethyl ester,n-propyl ester, iso-propyl ester, n-butyl ester, iso-butyl ester,sec.-butyl ester and tert.-butyl ester.

Compounds of the formula (III) are known (see J. Org. Chem. 32 (1967),3351; U.S. Pat. No. 3,644,487 and DE-OS (German Published Specification)No. 2,724,734).

3-Formyl-2,2-dimethyl-cyclopropane-1-carboxylic acid esters are obtainedfrom theα-oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methanephosphonicacid esters of the formula (I) by reaction with reducing agents, forexample sodium tetrahydridoborate (sodium boranate), if appropriateusing diluents, for example water and/or methanol and/or methylenechloride, at temperatures between -20° and +50° C., preferably between-10° and +30° C., and reaction of the resultingα-hydroxy-α-(3-alkoxycarbonyl-2,2-dimethylcycloprop-1-yl)-methane-phosphonicacid esters with aqueous alkali metal hydroxide solutions, for exampleaqueous sodium hydroxide solution, if appropriate in the presence of awater-immiscible solvent, for example methylene chloride, attemperatures between 0° and 100° C., preferably between 10° and 50° C.,in accordance with the equation below (see Chem. Ber. 103 (1970),2984-2986): ##STR11##

3-Formyl-2,2-dimethyl-cyclopropane-1-carboxylic acid esters can be usedas intermediate products for the preparation of insecticidally andacaricidally active pyrethroids (see DE-OS (German PublishedSpecification) No. 2,326,077).

EXAMPLE ##STR12##

A solution of 12 g of potassium hydroxide in 12 ml of water mixed with55 ml of saturated potassium carbonate solution was added to anintensively stirred solution, cooled to 10° to 15° C., of 52 g (0.2 mol)of tetramethylene-sulphonium-acetic acid ethyl ester bromide in 180 mlof chloroform. The reaction mixture was stirred at 10° C. for 15 minutesand then filtered. The two phases of the filtrate were separated. Thechloroform phase was dried over sodium sulphate and, after filtration,the solvent was carefully distilled off from the filtrate under reducedpressure, during which the bath temperature did not exceed 30° C. Theproduct which remained was employed attetramethylenesulphuranylidene-acetic acid ethyl ester (100% pure).##STR13##

83 g (0.5 mol) of triethyl phosphite were added dropwise to a solutionof 60 g (0.5 mol) of β,β-dimethylacrylic acid chloride in 200 ml ofmethylene chloride in the course of one hour. The reaction mixture wasstirred for a further hour at 40° to 45° C.; the solvent was thendistilled off under reduced pressure and the crude product whichremained was purified by vacuum distillation. 90 g (82% of theory) of1-oxo-3-methyl-2-butene-phosphonic acid diethyl ester of boiling point72° C./0.01 mbar were obtained.

Elementary analysis: calculated: C 49.1%; H 7.7%; O 29.1%; P 14.1%;found: C 48.5%; H 7.6%; O 28.9%; P 13.4%. ##STR14##

36 g (0.2 mol) of tetramethylenesulphuranylidene-acetic acid ethyl esterwere added to a solution of 44 g (0.2 mol) of1-oxo-3-methyl-2-butene-phosphonic acid diethyl ester in 150 ml oftoluene in the course of 10 minutes. During this addition, the internaltemperature rose to about 55° C. The reaction mixture was stirred forsome hours; the solvent was then carefully distilled off under reducedpressure. 58 g (95% of theory) ofα-oxo-α-(3-ethoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonicacid diethyl ester were obtained as an oily residue.

Elementary analysis: calculated: C 51.0%; H 7.5%; O 31.4%; P 10.1%;found: C 50.4%; H 7.4%; O 31.3%; P 9.7%.

It will be appreciated that the instant specification and examples areset forth by way of illustration and not limitation, and that variousmodifications and changes may be made without departing from the spiritand scope of the present invention.

I claim:
 1. A process for the preparation of anα-oxo-α-(3-alkoxycarbonyl-2,2-dimethyl-cycloprop-1-yl)-methane-phosphonicacid ester of the formula ##STR15## in which R is alkyl or a radicalcustomary in the alcohol component of pyrethroids, andR¹ is alkyl orphenyl, or the two radicals R¹ together are alkanediyl,comprisingreacting a 1-oxo-3-methyl-2-butene-phosphonic acid ester of the formula##STR16## with a sulphuranylidene-acetic acid ester of the formula##STR17## in which R² and R³ each independently is alkyl or together arealkanediyl, at a temperature between about 0° and 100° C.
 2. A processaccording to claim 1, wherein the reaction is effected in an inertorganic solvent.
 3. A process according to claim 1, wherein the reactionis effected at a temperature between about 20° and 80° C.
 4. A processaccording to claim 1, wherein about 0.9 to 1.1 mols of the acetic acidester are employed per mol of the phosphonic acid ester.
 5. A processaccording to claim 1, in which R¹ is C₁ -C₄ -alkyl or phenyl, or the tworadicals R¹ together are 2,2-dimethyl-propane-1,3-diyl.
 6. A processaccording to claim 1, in which R is C₁ -C₄ -alkyl, and R² and R³ areboth methyl or together are butane-1,4-diyl.
 7. A process according toclaim 1,in which R is C₁ -C₄ -alkyl, R¹ is C₁ -C₄ -alkyl or phenyl, orthe two radicals R¹ together are 2,2-dimethyl-propane-1,3-diyl, R² andR³ are both methyl or together are butane-1,4-diyl, and R⁴ is methyl orethyl, andwherein the reaction is effected in an inert organic solventat a temperature between about 20° and 80° C. employing about 0.9 to 1.1mols of the acetic acid ester per mol of the phosphonic acid ester.